Darwinian evolution requires genetic diversity plus competition that yields the survival of the fittest.

NPR: Startling New Evidence Cancer Is Contagious

His concern appears to be that evolution requires an unbroken chain of viable genetic variants that connect the first living creature to, say, human beings.

FORBES: The Darwinist 'Mob' That Wasn't

The evolutionary nature of cancer implies, contrary to conventional wisdom, that the essential features of any therapy for the consistent cure or control of cancer must be independent of the particular pathways of tumor cell evolution, and independent of any particular genetic or epigenetic alterations.

FORBES: Cancer's New Era Of Promise And Chaos

What we learn from these areas is precisely how evolution has acted to sculpt bodies, but it still does so using randomly-generated genetic variation and good old natural selection (and yes, Larry Moran, genetic drift also plays a role).

FORBES: Epigenetics: The Revolution That Wasn't